spatel created this revision.
Herald added a subscriber: mcrosier.
Splitting cbrt and fma off from https://reviews.llvm.org/D39611, so we can deal
with complex.h separately.
I've also gone ahead with a 'fix' for the fma case in
CodeGenFunction::EmitBuiltinExpr(). But as noted previously, there's no test
change because we were ignoring the const-ness of something that might have
been non-const. Now, we're correctly checking that attribute even though
there's no way it can be non-const. So if we change our minds about the fma
decision, we'll do it in the right place. :)
Copying from https://reviews.llvm.org/D39611:
1. Cube root
We're going to dismiss POSIX language like this:
"On successful completion, cbrt() returns the cube root of x. If x is NaN,
cbrt() returns NaN and errno may be set to [EDOM]. "
http://pubs.opengroup.org/onlinepubs/7908799/xsh/cbrt.html
And favor an interpretation based on the C standard that says:
"Functions with a NaN argument return a NaN result and raise no floating-point
exception, except where stated otherwise."
2. Floating multiply-add
The C standard is silent?
http://pubs.opengroup.org/onlinepubs/9699919799/functions/fma.html - clearly
says "...then errno shall be set..."
but:
https://linux.die.net/man/3/fma - "These functions do not set errno."
Let's opt for the - hopefully common - implementation where errno is not set.
Note that there's no test change because as noted in the earlier discussion,
we're ignoring the const attr in CodeGenFunction::EmitBuiltinExpr(). I'll look
at what needs fixing in that function next.
https://reviews.llvm.org/D39641
Files:
include/clang/Basic/Builtins.def
lib/CodeGen/CGBuiltin.cpp
test/CodeGen/builtin-errno.c
test/CodeGen/libcalls-errno.c
Index: test/CodeGen/libcalls-errno.c
===================================================================
--- test/CodeGen/libcalls-errno.c
+++ test/CodeGen/libcalls-errno.c
@@ -153,9 +153,9 @@
// NO__ERRNO: declare double @cbrt(double) [[READNONE]]
// NO__ERRNO: declare float @cbrtf(float) [[READNONE]]
// NO__ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[READNONE]]
-// HAS_ERRNO: declare double @cbrt(double) [[NOT_READNONE]]
-// HAS_ERRNO: declare float @cbrtf(float) [[NOT_READNONE]]
-// HAS_ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[NOT_READNONE]]
+// HAS_ERRNO: declare double @cbrt(double) [[READNONE]]
+// HAS_ERRNO: declare float @cbrtf(float) [[READNONE]]
+// HAS_ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[READNONE]]
ceil(f); ceilf(f); ceill(f);
Index: test/CodeGen/builtin-errno.c
===================================================================
--- test/CodeGen/builtin-errno.c
+++ test/CodeGen/builtin-errno.c
@@ -198,9 +198,9 @@
// NO__ERRNO: declare double @cbrt(double) [[READNONE]]
// NO__ERRNO: declare float @cbrtf(float) [[READNONE]]
// NO__ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[READNONE]]
-// HAS_ERRNO: declare double @cbrt(double) [[NOT_READNONE]]
-// HAS_ERRNO: declare float @cbrtf(float) [[NOT_READNONE]]
-// HAS_ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[NOT_READNONE]]
+// HAS_ERRNO: declare double @cbrt(double) [[READNONE]]
+// HAS_ERRNO: declare float @cbrtf(float) [[READNONE]]
+// HAS_ERRNO: declare x86_fp80 @cbrtl(x86_fp80) [[READNONE]]
__builtin_ceil(f); __builtin_ceilf(f); __builtin_ceill(f);
Index: lib/CodeGen/CGBuiltin.cpp
===================================================================
--- lib/CodeGen/CGBuiltin.cpp
+++ lib/CodeGen/CGBuiltin.cpp
@@ -2109,15 +2109,11 @@
case Builtin::BIfmal:
case Builtin::BI__builtin_fma:
case Builtin::BI__builtin_fmaf:
- case Builtin::BI__builtin_fmal: {
- // Rewrite fma to intrinsic.
- Value *FirstArg = EmitScalarExpr(E->getArg(0));
- llvm::Type *ArgType = FirstArg->getType();
- Value *F = CGM.getIntrinsic(Intrinsic::fma, ArgType);
- return RValue::get(
- Builder.CreateCall(F, {FirstArg, EmitScalarExpr(E->getArg(1)),
- EmitScalarExpr(E->getArg(2))}));
- }
+ case Builtin::BI__builtin_fmal:
+ // A constant libcall or builtin is equivalent to the LLVM intrinsic.
+ if (FD->hasAttr<ConstAttr>())
+ return RValue::get(emitTernaryBuiltin(*this, E, Intrinsic::fma));
+ break;
case Builtin::BI__builtin_signbit:
case Builtin::BI__builtin_signbitf:
Index: include/clang/Basic/Builtins.def
===================================================================
--- include/clang/Basic/Builtins.def
+++ include/clang/Basic/Builtins.def
@@ -165,9 +165,9 @@
BUILTIN(__builtin_atanh , "dd", "Fne")
BUILTIN(__builtin_atanhf, "ff", "Fne")
BUILTIN(__builtin_atanhl, "LdLd", "Fne")
-BUILTIN(__builtin_cbrt , "dd", "Fne")
-BUILTIN(__builtin_cbrtf, "ff", "Fne")
-BUILTIN(__builtin_cbrtl, "LdLd", "Fne")
+BUILTIN(__builtin_cbrt , "dd", "Fnc")
+BUILTIN(__builtin_cbrtf, "ff", "Fnc")
+BUILTIN(__builtin_cbrtl, "LdLd", "Fnc")
BUILTIN(__builtin_ceil , "dd" , "Fnc")
BUILTIN(__builtin_ceilf, "ff" , "Fnc")
BUILTIN(__builtin_ceill, "LdLd", "Fnc")
@@ -198,9 +198,11 @@
BUILTIN(__builtin_floor , "dd" , "Fnc")
BUILTIN(__builtin_floorf, "ff" , "Fnc")
BUILTIN(__builtin_floorl, "LdLd", "Fnc")
-BUILTIN(__builtin_fma, "dddd", "Fne")
-BUILTIN(__builtin_fmaf, "ffff", "Fne")
-BUILTIN(__builtin_fmal, "LdLdLdLd", "Fne")
+// Disregard that 'fma' could set errno. This is based on the assumption that no
+// reasonable implementation would set errno and harm performance of a basic op.
+BUILTIN(__builtin_fma, "dddd", "Fnc")
+BUILTIN(__builtin_fmaf, "ffff", "Fnc")
+BUILTIN(__builtin_fmal, "LdLdLdLd", "Fnc")
BUILTIN(__builtin_fmax, "ddd", "Fnc")
BUILTIN(__builtin_fmaxf, "fff", "Fnc")
BUILTIN(__builtin_fmaxl, "LdLdLd", "Fnc")
@@ -1040,9 +1042,9 @@
LIBBUILTIN(atanhf, "ff", "fne", "math.h", ALL_LANGUAGES)
LIBBUILTIN(atanhl, "LdLd", "fne", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(cbrt, "dd", "fne", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(cbrtf, "ff", "fne", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(cbrtl, "LdLd", "fne", "math.h", ALL_LANGUAGES)
+LIBBUILTIN(cbrt, "dd", "fnc", "math.h", ALL_LANGUAGES)
+LIBBUILTIN(cbrtf, "ff", "fnc", "math.h", ALL_LANGUAGES)
+LIBBUILTIN(cbrtl, "LdLd", "fnc", "math.h", ALL_LANGUAGES)
LIBBUILTIN(ceil, "dd", "fnc", "math.h", ALL_LANGUAGES)
LIBBUILTIN(ceilf, "ff", "fnc", "math.h", ALL_LANGUAGES)
@@ -1084,9 +1086,11 @@
LIBBUILTIN(floorf, "ff", "fnc", "math.h", ALL_LANGUAGES)
LIBBUILTIN(floorl, "LdLd", "fnc", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(fma, "dddd", "fne", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(fmaf, "ffff", "fne", "math.h", ALL_LANGUAGES)
-LIBBUILTIN(fmal, "LdLdLdLd", "fne", "math.h", ALL_LANGUAGES)
+// Disregard that fma could set errno. This is based on the assumption that no
+// reasonable implementation would set errno and harm performance of a basic op.
+LIBBUILTIN(fma, "dddd", "fnc", "math.h", ALL_LANGUAGES)
+LIBBUILTIN(fmaf, "ffff", "fnc", "math.h", ALL_LANGUAGES)
+LIBBUILTIN(fmal, "LdLdLdLd", "fnc", "math.h", ALL_LANGUAGES)
LIBBUILTIN(fmax, "ddd", "fnc", "math.h", ALL_LANGUAGES)
LIBBUILTIN(fmaxf, "fff", "fnc", "math.h", ALL_LANGUAGES)
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